Export Data to Excel file from Sql Server using C# coding

System.Data.DataTable dtMainSQLData = new System.Data.DataTable();
da.Fill(dtMainSQLData);
DataColumnCollection dcCollection = dtMainSQLData.Columns;
// Export Data into EXCEL Sheet
Microsoft.Office.Interop.Excel._Application ExcelApp = new Excel.Application();
ExcelApp.Application.Workbooks.Add(Type.Missing);


// ExcelApp.Cells.CopyFromRecordset(objRS);
for (int i = 1; i < dtMainSQLData.Rows.Count + 1; i++)
{
   
    for (int j = 1; j < dtMainSQLData.Columns.Count + 1; j++)
    {
        if (i == 1)

            ExcelApp.Cells[i, j] = dcCollection[j - 1].ToString();
            
        else

            ExcelApp.Cells[i, j] = dtMainSQLData.Rows[i - 1][j - 1].ToString();

        

    }
}
ExcelApp.ActiveWorkbook.SaveCopyAs("E:\\1.xls");
ExcelApp.ActiveWorkbook.Saved = true;
ExcelApp.Quit();
MessageBox.Show("Data Exported Successfully");

header				L	U	R
						
						
Sr.no	A	B	C	1	1	1
1	Particular A	A	11	1	0	0
2	Particular A	B	12	5	0	0
	Particular A			7	1	1
						
3	Particular B	A	13	5	1	0
4	Particular B	B	14	0	0	3
	Particular B			5	1	3